Everton manager David Moyes has confirmed that midfielder Marouane Fellaini will miss the rest of the season following ankle surgery.
Moyes also confirmed that Australia international Tim Cahill will be out for up to two weeks with a foot problem.
Belgium international Fellaini sat out the final three months of last season with an ankle ligament injury and six weeks of this season with a hamstring problem.
He sustained the latest knock during Everton’s 2-0 win over Sunderland on Saturday.
The 23-year-old will undergo surgery next week and is not expected to be available again this season.
“Marouane is going to be out for the season now, he will have an operation on Monday,” Moyes said.
“Everybody who has watched us will tell you he has been a key player for us and Tim Cahill will probably miss two or three weeks as well.”
Moyes was speaking after his side’s fifth-round FA Cup defeat at home to Championship Reading.
Everton beat English Premier League title holders Chelsea in the fourth round, but went down 1-0 against second-tier opposition at Goodison Park on Tuesday.
“It’s a massive disappointment for us because we did so well in the previous round,” Moyes said.
“You can only ask for a home tie and we didn’t take advantage of it.”
“We could have defended the set-piece for the goal, our attacking wasn’t good enough. I think they defended really well.”
“They got back behind the ball and we didn’t have enough craft at the top of the pitch to make things happen.”